The present invention relates generally to an introducer and dilator for insertion of medical devices into a patient. More particularly, it pertains to an introducer and dilator which lock together.
Introducer devices are employed for inserting catheters, guide wires, or other medical devices into patients. A typical procedure provides for insertion of a needle into the vasculature of a patient. After insertion of the needle, a guide wire is inserted through the needle, and the needle is removed. The dilator and the sheath are inserted over the guidewire, and the dilator may be removed leaving the sheath protruding from the patient""s vein. A diagnostic or therapeutic catheter (e.g. a central venous access catheter) or guide wire or other medical device, is then inserted through the sheath into the patient.
When the dilator and sheath are inserted over the guidewire, and the medical technician is attempting to drive the dilator through the skin, subcutaneous tissue and the wall of the vein, there is a tendency for the dilator to retract toward the sheath. The retraction of the dilator can result in trauma to the patient, and can also make the implanting process awkward and imprecise for the medical technician. When the dilator recedes to a position where the distal end of the dilator is within the sheath, the relatively large sheath causes a puncture at the entry site which is painfully traumatic to the patient. In addition, there are risks of tearing of the tissue adjacent to the entry site. Further, forcing the sheath into the entry site can result in bending or kinking of the sheath, which can allow the sheath to bend or kink resulting, and a new puncture site would be necessary. Therefore, it is important to lock or fasten the dilator and sheath to each other during the insertion process.
One type of locking device is provided in U.S. Pat. No. 5,879,333, which relates to a catheter which is snap-fitted with a cannula. However, this type of device allows for the cannula to pop out of the catheter unexpectedly, requiring the medical technician to manually hold the dilator and the sheath together during the insertion process despite the presence of the locking device. Another type of locking device is a threaded rotational locking device which locks a dilator to a sheath. However, as the threaded fastener is rotated, the dilator also rotates, resulting in complications and/or distraction to the medical technician during the implant procedure. Other distractions can occur when the medical technician uses a device for a first time, and when damage occurs to the device as a result of misuse.
Accordingly, what is needed is a locking introducer and dilator which do not become easily and/or unintentionally unlocked from one another during or after insertion into a patient. What is further needed is a locking introducer and dilator which do not distract the physician or medical technician during implant.
An introducing apparatus includes an elongate tubular sheath having an external diameter small enough to be readily insertable in a selected vein. The sheath has a bore which receives therein a dilator such that a distal end of the dilator projects from out from the distal end of the sheath. A rotatable fastener is rotatably coupled with the dilator, and couples the sheath with the dilator and prevents axial movement therebetween. A means of selectively rotating the dilator relative to the sheath includes an anti-rotation member which is associated with the dilator and/or the sheath. The anti-rotation member resists rotational movement of the dilator relative to the sheath as the rotatable fastener is rotated.
In another embodiment, an introducing apparatus includes an elongate tubular sheath having an external diameter small enough to be readily insertable in a selected vein. The sheath has a bore which receives therein a dilator such that a distal end of the dilator projects from out from the distal end of the sheath. A rotatable fastener is rotatably coupled with the dilator, and couples the sheath with the dilator and prevents axial movement therebetween. A hub of the dilator includes an elliptical cross-section which corresponds to the cross-section of the sheath which resists relative rotational movement between the dilator and the sheath.
The introducer assembly allows for the medical technician or physician to rotatably lock the sheath and the dilator to one another without unintentionally rotating one relative to the other during the procedure or during the implant. This improves the implanting process and reduces potential pain or damage to the vasculature of the patient. In addition, the medical technician or physician will not become distracted by components inadvertently rotating or by the components separating from each other. A further benefit includes the ability of the introducer apparatus to withstand damage or separation of the sheath should the medical technician apply excessive torque to the dilator, whether intentional or unintentional. Furthermore, the introducer apparatus allows for the dilator to selectively rotatable without any damage occurring to the sheath and/or the dilator.
These and other embodiments, aspects, advantages, and features of the present invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art by reference to the following description of the invention and referenced drawings or by practice of the invention. The aspects, advantages, and features of the invention are realized and attained by means of the instrumentalities, procedures, and combinations particularly pointed out in the appended claims and their equivalents.